In early universe, matter phase was like hot fluid and was symmetric in all directions, as in gas or liquid, not as in asymmetric crystals. Later cooling changed matter phase differently at different places, and different space regions had different ground-state energies. Boundaries formed between different-phase regions. As universe expanded, boundaries stretched into long strings {cosmic string}. Cosmic strings have large mass, positive energy, and positive pressure.
Physical Sciences>Physics>Matter>Particle
Outline of Knowledge Database Home Page
Description of Outline of Knowledge Database
Date Modified: 2022.0224